Dissolved vapor in aircraft and missile fuels may pose serious problems. If the vapor begins evolving when the vehicle is in flight, it may interrupt or stall the engine. This problem is particularly severe in drones or missiles in which the fuel may be stored in a sealed tank on the vehicle for an extended period before use If excessive vapor is present at engine start-up, the vehicle may fail to start or may stall.
The only prior system of which applicant is aware, which attempts to minimize the problems associated with dissolved vapor in fuel is one which utilizes the use of three separate devices. This system requires a tank mounted booster pump. The booster pump supplies vapor laden fuel to a separator tank. In the separator tank, the vapor is allowed to boil out of the liquid and the liquid phase is supplied to the suction side of a metering pump. The metering pump delivers the fuel at a controlled rate to the engine.
A problem with existing systems is that they are expensive due to the use of multiple components. In addition, the two pumps in such systems consume large amounts of power and add weight; two very undesirable characteristics for lightweight vehicles Increasing the number of interdependent components in a fuel system also increases the probability of failure.
Thus, there exists a need for a vapor separating and fuel metering apparatus for an aircraft or missile that is lightweight, compact and uses less power than apparatus currently in use. There further exists a need for a vapor separating and fuel metering apparatus that reliably functions regardless of acceleration forces on the vehicle.